Energy harvesting from low-energy-density sources such as wind turbulence and structural vibration has been a hot topic for research, and much work has been invested world-wide. The typical application for energy harvesting has been for powering sensors and wireless communications nodes.
In a hydraulic system, distributed sensors are common, and health-monitoring systems are being deployed within the hydraulics industry, and remote sensing and monitoring is common in processing industries. Whereas the commonly explored energy harvester technologies developed to date (e.g., wind turbulence and structural vibration) have been applied to energy sources of relatively low energy density, hydraulic pressure fluctuations (i.e., the pressure ripple in a hydraulic system) represent a relatively high energy density source by comparison. The pressure ripple present within most hydraulic systems, or within any fluid system subject to pumping action, is commonly viewed as an annoyance or a detriment to system performance; however, the pressure ripple may also represent a power source for energy harvesting.
Therefore, there is a long-felt but unresolved need for systems or methods that harvest energy from the pressure ripple present within a hydraulic or other fluid system.